The convention for a node on the Internet network is:
machine.section.organization.type_of_organizationwhere type_of_organization may be edu, mil, gov, com, org, net or, outside of the United States, country_code.
As of 2001, type_of_organization also includes aero, biz, coop, info, museum, name and pro. The networking section (part II of the course notes) will explain in more details what they are.
At the National Research Council, a node is defined as
machine.institute.nrc.caThe Research Computing Support Group's SGI O is nickel.sao.nrc.ca for the outside world, nickel.sao for people within NRC and nickel for people within RPSO/SCSG.